Great question! VEC doesn't make it obvious. However it's super easy I'll show you how in the recording below. (Click on the video to make it bigger!) If you feel I've been helpful please take a moment to like, mark as helpful and mark as answer. Hope you have a wonderful day!
You are correct. This 'mbox' option is available to select the mbox on the oage where you want to make any modification. Content is to write your script, which you would want to run in the selected mbox. Hope that clarifies.
Thanks Mihnea, I have one more question. Under modification, there is an option for mbox. When i select mbox, there is an option for content, could you give me idea what can i write in content? Is it for script?